Process of preparing desiccated vegetable extracts.



P. KESTNER. PROCESS OF PREPARING DESIGGATED VEGETABLE EXTRAGTS APPLICATION FILED APR. 19, 1909.

, 1 005 554. Patented Oct. 10, 1911.

mzwsw PM fiQZd/i l/MTUZL UNITED; STATES PATENT OFFICE.

PAUL KE'srNER, or LILLE, FRANCE.

7 Specification of Letters l Pa tent. i Patentd 0017.10, 1911.

' Application filed April 19, 1909. Serial No. 490,804.

To all whom it may concern:

Be it known that I," PAUL-KEs'rNER, a citizen of the'Republic of France, and a resident of Lille, Department of the Nord, France, have invented certain Improvements in Processes of Preparing Desiccated Vegetable Extracts, ofwhich'the following is a specification. I

This invention relates to" desiccated vegetable. extracts and processes of preparing same; and it comprises a method of preparing'a dry, light and flufly product from gummy and viscous vegetable extracts, wherein such an extract'is concentrated to a relatively thick consistency, and is then-temporarily heated to a relatively hi h temperature; and in order to secure the ufi'y product it is allowed to expand into a vacuum chamber; and it also comprises the product of such process; all'as more fully herein set forth and as claimed. Many vegetable extracts, such as those obtained fro'm -the common dyestuffs, such as logwood, fu sti'c"(both young and old fustic), the tannic extracts, quebracho'extract, licorice, medicinal extracts, fruitjuices, such as grape ju'ice,et c;, prepared with-water, alcohol and other extractive means are gummy a-ndvlscous when concentratedand are difficult toprepare in the commercially desirableform of dry powders,indefinitely permanent and easily"dispensed and handled. As they occur in the markets, theseextr'acts,

when in concentrated form, are generally hard, tarry or asphalt like masses which are not readily handled. 'Many attempts have been made in the/past to prepare desiccated products from'these extracts without chemically changing their character, and without adding foreign matter, but these attempts have not beenvparticularly successful. Logwood extract manufacturers, asa matter of fact,ihave been forced to add such potent chemicals as ,n'itrites to their prepartion to enable, them to produce a dry powder on evaporation. The nitrites, of course, change the bodies contained in the extract somewhat, butvthe convenience of the dry powder form outweighs the disadvantage of this change. In other methods, various inert foreign bodies are mixed with'and'dilute the extract.

v If extracts,'such as wood'extracts for example, beconcentrated to very high densities, it is possible to dehydrate themto such a point that while they remain fluid when hot, they solidify when simply cooled. It is necessary in this case, therefore, to make the final concentrationeither in the 0 en air or at a temperature ofabout 100. and generally above 100 C., in order tohave a suflicient temperature to obtain this-degree of concentration. 'In the solid state, in which condition the extracts appear when cooled they are not generally easy to use and as they are usually resinous or gummy, they are 'difiicult to grind and reduce to'powder, for they choke the mills. I have found that by taking these extracts and submitting them while at as-high a temperature as possible to the influence of vacuum, I-immediately obtain solids, but in a spongy form which I believe'to be absolutely new. On passing into the vacuum,' a small proportion" of the remaining water passes ofi through selfevapora'tion- This proportion :(usually from 2- to "5%) varies according .to'the temperature to which the extract hasabeen heat" ed; and the steam yielded not being able to free itself easily, aerates "the mass, which hardens while-cooling" to the-temperature viscous mass which will not circulate in the ordinary types of evaporating apparatus and cannot easily be evaporated further therein: Further evaporation of the thick mass in'bulk', as in using ordinarytvacuum pans, ispractically impossible. For further desiccation, it is, therefore, necessary to use drying apparatus which isexpensive and complicated, and which does not'give satisfactory, results for this purposehIt is always supposed that with extracts of this character it'isdangeroustjo use anybut a relatively low temperature in evaporation. This, however, is an error. Suchextracts may be safely heated to a much'h'igher'tem- V perature,

' high temperature, preferably under even to a number of degrees above 100 C., if this high heating be only temporary. Generally, the high heat should not last more than a couple of minutes. A temporary application of the high temperature is not dangerous. In the present invention, I have devised. a cheap, simple and ready method of preparing dry extracts of advantageous properties based on this fact.

I preliminarily evaporate the extract in vacuum evaporators or the like until it attains a sirupy consistency say, with 30 to 50 per cent. of water, the exact amount, of course, depending upon the particular. extract treated and its behavior on evaporation. The evaporation should be carried as far as is easily practicable. This preliminary evaporatlon may be done in the ordinary multiple eflect apparatus, or in any other suitable evaporator working under ordinary or minus pressure. The concentrated thick liquid thus prepared is next exposed to heat and evaporation at a relatively some pressure above atmospheric pressure. This heating should be as quick as possible. At temperatures around 100 0., these thick extracts become sufliciently fluid to permit.

circulation in the evaporating apparatus, and under these conditions evaporation to 8 or 10 percent of water may be effected. While this heating and evaporationmay be effected in mass or bulk, this is difficult -without special apparatus and I prefer apparatus using some type of film evaporation, and I particularly prefer what is known as the Kestner type. This film evaporator preferably Works under some degree of pressure and at a relatively high temperature.

After the reduction to the desired per cent. of water,-with a water extract, is obtained, the 'hot material in the present embodiment of my invention is transferred to a vacuum chamber and allowed to expand therein. Much of the contained water in the heated material will at once flash into vapor when such material enters thevacuum chamber and this vapor will be. formed in every portion of the mass, indefinitely expanding it and forming a light, fluffy, vesiculated material, and particularly with extracts containing much colloid matter. Where the material enters the vacuum chamber, as

itordinarily does, through a relatively narrow'jet nozzle, the product as collected will usually have the form of spongy vermicular bodies, physically somewhat like the ordi nary Pharaohs serpent It may becomminuted to form a very light, fluffy powder,

composed of flaky, curvllinear or irregularsurfaced particles, which may be preserved indefinitely and which upon the addition of Water will reform the original extract. No

foreign substances or chemicals having been added in the operation, the .solution thus obtained is substantially the same as the original extract. v

The foregoing process is applicable for the treatment of any vegetable extract containing gummy and colloid bodies, such as vegetable extracts employed for dyeing, mordanting, medicine, food, tanning, etc. Besides all wood extracts-ches'tnut, oak, logwood, .quebracho, licorice, etc. I can also wood pulp obtained by the bisulfite process, which is in fact a vegetable extract. obtain from this last a dry extract for use, for example, as a binder for coal and min- I can treat by the same process organic extracts or secretions such as milk, extract of meat, and a number of other products, and in general, all products which are fluid when hot and solid whencold. and which contain at least some percent of water. I may also start with a concentrated product, even of such concentration that it is solid when cold. It must however be capable of liquefaction upon heating, or if not so capable, enough water must be added to make it so. With any such concentrated product there must be a certain amount of water present and capable of self-evaporation upon reduction of pressure to enable such material to be treated by the present process. Such a product may be heated in the open air or under pressure to obtain fluidity and the desired temperature and mayv then be introduced into the vacuum chamber. The water present and capable of self-evapora tion then flashes into vapor and the material expands and becomes vesicular.

While other forms of high temperature evaporators may be employed for the purpose of increasing the density of the liquid or securing a high degree of concentration, I prefer to employ an apparatus of the type illustrated in my application for patent filed May 29, 1906, Serial No. 319,386, in which the liquid material is caused toascend in the form of films and subsequently descend in the same form under the influence of heat, in a series of tubes contained within a suitable heating shell.

As most organic extracts are sensible to ed to it for any length o time, I must as far as possible have recourse to an evaporator concentrating very rapidly and in a single circulation, such as the one referred to which is represented in the drawing. Mostof the extracts can undergo without alteration a. temperature considerably above 100 (1, on condition that it does not last more than one gor two minutes, as is the case with the apparatus mentioned. The liquid sent to such form of evaporator may be relatively thick and is preferably so in order that the final treat bythis process the wash water of' the action of a high tem erature if subject eral ores as a substitute for rosin or pitch. 5

ture illustrated in Fig. 1. The internal arrangement of this form'of the apparatus is the same as illustrated in Fig. 2, and the steam produced Within the evaporator from the liquid undergoing treatment ma escape through a relief valve 8 connecte to the outlet 8, by which I can obtain the desired back pressure if I wish to make the evaporation at a pressure above that of the atmosphere. Inthis form of a paratus, the extract'to be concentrated is ed at 5, and the finished extract is discharged through a curved outlet pipe 16, which may be coupled to a nozzle 12 leading to the vacuum chamber within the shell or casing 10.

In the form of apparatus shown in Fig. 1, connection is made directly to the chamber in which desiccation takes place, and as in the use of such form of apparatus the output would be relatively limited, I may, therefore, provide an apparatus such as shown in Fig. 3, in which a series of desiccation chambers are provided, having nozzles 12 to each of which the curved outlet pipe 16 may be directed as the chambers are successively emptied. By employing a series of vacuum chambers as in Fig. 3, it is possible to have a continuous performance of the apparatus.

In the apparatus shown in the drawings, the concentrated extract enters the chamber b a single opening controlled by a valve 1% I can of course vary the size of the inlet by the number of openings used, and I may obtain a corresponding number of worms, whose diameters will decrease as I increase the number of openings. The density of this matter is extremely light. It is so light that I can, as stated above, reduce it to a powder very easily by crushing it between the fingers. This powder as well as the uncrushed product dissolves very easily.

While other materials than gummy and viscous vegetable extracts may be treated by the described process with advantage, such as milk, acetate of lime, tar, etc., yet I regard the invention in its present preferred embodiment as particularly adapted to such vegetable extracts. The described operation may also be performed at somewhat lower temperatures, though in some instances less advantageously. The question of temperature, however, is a relative one and depends entirely upon the materials treated. Assuming therefore that the material may safely stand a higher temperature it will be understood that a concentrated liquid of, say 100 C. temperature, may be projected into a vacuum chamber with a production of the same result.though of course in a less degree than if.. -projected at a higher temperature and pressure. The hotter the liquid or material entering the vacuum chamber, the greater will be the flufing or desiccation produced, and it is therefore, usually advanexpand in a vacuum.

tageous to introduce the material at a temperature somewhat above 100 C, and as I claim 1. The process of drying gummy and viscous extracts which comprises evaporating such extracts to a thick consistency, momentarily raising the temperature of the thickened extract to a point higher than the temperature at which it was evaporated, and then allowing the highly heated extract to 2. The process of drying gummy and viscous ve etable extracts which comprises preliminarily evaporating such extracts to a thick consistency, causing the extract to traverse a highly heated evaporator in rapidly moving films until the major amount of residual liquid is removed, and then allowing the highly heated, highly evaporated material to expand in a vacuum to remove the remaining volatile moisture.

3. The process of drying gummy and viscous vegetable extracts WlllCll comprises preliminarily evaporating such extracts to a thick consistency, causing the extract to traverse an evaporator heated above 100 C. in rapidly moving films until the major amount of residual liquid is removed, and then allowing the highly heated, highly evaporated material to expand in a vacuum to remove the remaining volatile material.

4. A method of producing a dry extract which consists in finishing the concentration of a partially. concentrated extract at a temperature above 100 C. and. carrying the concentration to such an extent that if cooled the extract would become solid, and then discharging the hot extract thus obtained in'fluid state into a Vacuum whereby, if concentration has been carried high enough, a substantially solid, dry and porous extract is obtained.

5. A method of producing dry extracts consisting in heating to a temperature above 100 0., a concentrated extract containlng at least enough water to be in a liquid state, and then allowing this superheated liquid to suddenly expand in a vacuum.

6. The process of drying gummy and viscous vegetable extracts, which comprises subjecting such extractsto an evaporating heat,

the final stages of'such heating being per-.

mospheric and at a temperature above 100 (1, and the evaporation being carried sufli ciently far to cause the extract to be dry at name to this specification, in the presence of atmospherig temperatulrle, said 1pressurz bletwo subscribing witnesses. ing release rior to t e comp etion 0 t e v evaporation v hereby vapor flashes into ex- PAUL KESTNER' istence throughout the mass of material Witnesses under treatment. HENRI CHARRIER,

In testimony whereof, I have signed my LION PECKEL. 

